Seagrass habitats are valuable coastal ecosystems in maintaining marine biodiversity and mitigating climate change by absorbing and storing carbon. The Special Monitoring and Coastal Environment Assessment Regional Activity Centre (CEARAC) of the Northwest Pacific Action Plan (NOWPAP) organised its first webinar for mapping seagrass by optical sensors from 30 November to 02 December 2021. About 50 participants have registered for the webinar. During the webinar, participants learned key factors for accurate mapping of seagrass habitats and got familiarised with the Seagrass Trainer and the Seagrass Mapper. Capacity building in the field of ocean remote sensing in the NOWPAP region is one of the mandated tasks of CEARAC. NOWPAP will continue these capacity building efforts for mapping seagrass by remote sensing so that regional-based monitoring of seagrass habitats in the NOWPAP region.